… is said to be so small, in a way (5)
I believe the answer is:
sweet
'is said to be' is the definition.
I can't tell whether this definition defines the answer.
'small in a way' is the wordplay.
'small' becomes 'wee' (Scottish term for small).
'in' means one lot of letters goes inside another.
'a way' becomes 'st' (abbreviation for street).
'wee' put inside 'st' is 'SWEET'.
'so' is the link.
Can you help me to learn more?
(Other definitions for sweet that I've seen before include "Afters" , "S [SWEET] , basically" , "Having a sugary taste" , "Pleasing" , "Pudding" .)